Abstract

"The average air temperature at the Earth's surface has
increased by 0.06 °C per decade during the 20th century, and by
0.19 °C per decade from 1979 to 1998. Climate models generally
predict amplified warming in polar regions, as observed in
Antarctica's peninsula region over the second half of the 20th
century. Although previous reports suggest slight recent
continental warming9, 10, our spatial analysis of Antarctic
meteorological data demonstrates a net cooling on the Antarctic
continent between 1966 and 2000, particularly during summer and
autumn. The McMurdo Dry Valleys have cooled by 0.7 °C per decade
between 1986 and 2000, with similar pronounced seasonal trends.
Summer cooling is particularly important to Antarctic terrestrial
ecosystems that are poised at the interface of ice and water. Here
we present data from the dry valleys representing evidence of rapid
terrestrial ecosystem response to climate cooling in Antarctica,
including decreased primary productivity of lakes (6–9% per year)
and declining numbers of soil invertebrates (more than 10% per
year). Continental Antarctic cooling, especially the seasonality of
cooling, poses challenges to models of climate and ecosystem
change."